The Gunners had looked to have been the architects of their own downfall, with two mistakes costing them dearly and giving Benfica the advantage going into the closing stages. However, Pierre-Emerick Aubameyang and Bukayo Saka combined in the 87th minute to ensure the Gunners' dream lives on.
Arsenal had been in control in the first half and led the tie 2-1 on aggregate. Aubameyang and Saka had started brightly and the two linked up for Aubameyang to open the scoring, the skipper breaking Benfica's high line to lift the ball into the net. Both players had other chances to score but just as Arsenal looked to be in control, Benfica earned a free kick that Diogo Goncalves finished with aplomb.
In the second half, Rafa Silva seized a poor headed back pass from Dani Ceballos to put Benfica ahead on the night, and on aggregate. Arsenal though did not quit, Kieran Tierney pulling the Gunners' level with a stunning low drive following neat work from Willian on 67 minutes, before Aubameyang popped up with the late decider.
Mikel Arteta will have been delighted with the way his side battled back into the game after having gone 2-1 down. They showed great spirit to pull themselves level, particularly as they had looked so fragile at the start of the second half. Saka was the bright spark in the final third.
Arsenal made mistakes that could have knocked them out of the competition. Ceballos was guilty of two howlers tonight, but it's a case of Groundhog Day for the Londoners.
Manager rating out of 10
5 -- Questions will be asked of Arteta's starting line-up, with Hector Bellerin picked ahead of Cedric Soares and Thomas Partey left on the bench. Emile Smith-Rowe looked lost on the left, too. The introduction of Willian did lead to an equaliser, but Arsenal looked disjointed throughout. He got away with this one...
Player ratings (1-10; 10 = best. Players introduced after 70 minutes get no rating)
GK Bernd Leno, 5 -- In his 100th appearance for the club, Leno had little to do until he picked the ball out of the back of the net following Goncalves stunning free kick. He could little about the second too after Bellerin's careless back pass left him in no man's land.
DF Hector Bellerin, 4 -- Bellerin was indecisive on the ball at times, which probably left Gunners fans wondering why he'd started ahead of Cedric. It meant that Saka didn't see the ball on the right-hand side as much as he probably should have.
DF Kieran Tierney, 6 -- The Scot got forward on occasion and his equaliser gave Arsenal hope of a late rally. Tierney gave himself a yard to shoot inside the box and his low, left-footed drive was unstoppable.
DF Gabriel Magalhaes, 5 -- Not Gabriel's finest evening in an Arsenal shirt. Together with David Luiz, they lacked confidence as a duo and there were often holes left for Benfica to exploit.
DF David Luiz, 5 -- The Brazilian defender looked edgy throughout. Benfica were poor in the final third but were given far too many chances.
MF Granit Xhaka, 5 -- He didn't do a lot wrong but he appeared to slow play down when in possession. There's something about the Xhaka-Ceballos axis in midfield that just didn't work.
MF Dani Ceballos, 3 -- The Spaniard had an awful evening. It was from his lunge on the edge of the area, when he stuck out his leg rather than moving his feet to get across his man, that Benfica earned a free kick and pulled themselves back into the tie. Then, in the second half, his failed headed back pass allowed Silva to give Benfica the lead.
MF Martin Odegaard, 5 -- Controlled possession well at times and rarely gave the ball away. However, he was guilty of being too conservative in the final third and occupied the same pockets of space that Saka was looking to utilise.
FW Emile Smith-Rowe, 5 -- Linked up well with Saka in the final third at times, though he wasn't always on the same wavelength when it came to the final ball. Utilised on the left instead of IN the No.10 role, he didn't seem to be able to impact the game as much from wide.
FW Bukyo Saka, 8 -- Started on the right and looked dangerous. He was influential in the opening goal, when he cut in from the right and played a precise ball through to Aubameyang for his 17th assist with the club. His 18th led to the winner, Saka again finding Aubameyang, this time with a perfectly whipped in cross.
FW Pierre-Emerick Aubameyang, 7 -- The skipper opened the scoring with his 30th goal in European competitions with a neat finish. He played on the shoulder of the last defender, narrowly beat the offside trap with a perfectly timed run, and dinked the ball home. He thought he'd bagged a second after the break in similar fashion, but it was adjudged to be offside. However, he made up for it with minutes left on the clock when he netted a dramatic winner to keep Arsenal's European dream alive.
MF Willian, 6 -- The Brazilian made an immediate impact when he broke free on the left and then passed to Tierney, who pulled Arsenal level. In the midst of a tough season, he certainly made a positive difference here.
MF Thomas Partey, 60 -- It can be no coincidence that when he came on to the pitch, Arsenal looked better. Should have started the game.
FW Alexandre Lacazette, N/R -- The Frenchman gave Arsenal a bit more of an attacking edge when he came on.
DF Callum Chambers, N/R -- Chambers was brought on to steady the ship in the closing stages.
MF Mohamed Elneny, N/R -- Had little time to impress but played his part as Arsenal ran down the clock.